Manufacturing laying head pipe path below transformation temperature

ABSTRACT

A rolling mill coil-forming laying head system elongated hollow pathway Or pipe structure defining an inner surface for transport of elongated materials is formed by the process of bending the pathway structure at near constant temperature, such as at near ambient temperature, preferably without application of external heat. In some embodiments, the method utilizes an automated bending machine, preferably under computer numerical control (CNC) that executes stored bending constructions to conform the pathway structure to a desired profile. The bending instructions may be modified so that the actual bending profile conforms to a desired profile. In this manner subsequent path structures may be formed, that have uniform physical properties.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 §119(e) toco-pending United States Provisional Patent Application Ser. No.61/540,671, filed 29 Sep. 2011, and is entirely incorporated herein byreference as if fully set forth below.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to a coil-forming apparatus,also known as a laying head system, in a rolling mill, and moreparticularly to a novel method of manufacturing a laying head pathwaystructure or pipe path for a laying head system by automated bending ofthick-walled tubing or other elongated pathway structure, includingnested multi-layer tubing below the constituent material'stransformation temperature.

2. Description of the Prior Art

The conventional method for producing a rolling mill coil-forming layinghead system elongated hollow pathway structure/laying head path is byheating tubes of various materials to a temperature of approximately1922° F. (˜4050° C.) sufficient to allow the tube to be bent in a manualfixture to a desired profile. This heating temperature is above thetransformation temperature of many materials, where they undergointernal atomic changes that affect their physical properties. In thecase of some metal alloys, heating them above their transformationtemperatures increases grain sizes within their grain structures, anddecreases metal hardness. Consistent adherence to desired profiledimension specifications (often tolerances within 1 mm (˜0.039 in) overa dimensional length of meters (yards) are required for properengagement with the coil-forming laying head quill and path supports androtational balance. As noted above, heating the tube material above itstransition temperature and subsequent cooling has detrimental effects onthe mechanical properties of the tube, e.g., material hardness, whichresults in a shorter service of the component. The hot-forming heatingand cooling cycle also introduces undesirable variances in tubingmechanical properties including by way of non-example, materialhardness, weight, center of rotating mass, surface finish and dimensionsduring the approximately one hour-long forming process. White the heatedtube is extracted from an oven at 1922° F. (˜1050° C.) its temperaturecools to approximately 1382° F. (˜7750° C.) by completion of theapproximately 100 second bending phase of a one hour-long formingprocess for each individual path/tube structure. The laying head pathelongated structure formation process of heating the tube, bending itand allowing it to cool before it can be post processed is timeconsuming and labor intensive. Subsequent localized manual re-bendingmay be required to conform the cooled tube to the desired dimensionalprofile specifications, for example to compensate for cooling cyclethermal distortion and/or structural “spring back” to pre-bendingdimensions. Manual “hot” laying path structure formation introducesconstruction. variances between different tubes and requires varyingremediation efforts to conform each individual tube to desireddimensional profile specifications. In addition, each time a new layinghead path is developed new fixtures are required, which define this pathand serve as the means by which the path is formed.

Conventional “hot” manual laying head system pathway structure formationis not readily compatible with a new generation of elongated pathwaystructures that may not have uniform tubular cross sections, or that maybe constructed of multiple nested and/or adjoining lateral segments ofmaterials having different physical properties as shown in theabove-referenced provisional patent applications. For example, amulti-layered laying path elongated structure formed from two or morenested layers of steel, nonferrous superalloys, composite non-metallicstructures and aluminum is not conducive to conventional “hot” bendingat temperatures of approximately 922° F. (˜1050° C.), because of thelower melting or burning temperature of the aluminum or compositelayers.

SUMMARY OF THE INVENTION

Briefly described, aspects of the present invention relate to a methodof manufacturing a laying head pipe pathway. In some embodiments, themethod can produce a laying head path below the transition temperatureof its constituent material, and in other embodiments at near ambienttemperature, thus eliminating the need for heating the tube to hightemperatures, and reducing variances in the pathway physical properties.Elimination of heating facilitates usage of multi-layer and/or adjoinedmulti-segment elongated pathway structures constructed of materialshaving different physical properties. In some embodiments, the methodutilizes automated computer numerical control (CNC) bending machines todefine and form the path mathematically, so that future changes to thepath simply require a change to the equipment program and not physicalforming tooling. The automated bending machine instruction sets utilizedin the CNC controller may be modified to correct and compensate fordeviations between an actual bent profile of a pathway structure and thedesired bent profile. The modified bending instructions are utilized tobend subsequently manufactured pathway structures that are in conformitywith the desired bent profile.

Embodiments of the present invention feature an apparatus for retentionand transport of elongated materials in a rolling mill coil-forminglaying head system comprising an elongated hollow pathway structuredefining an inner surface for transport of elongated materials therein.The apparatus is formed by the process of bending the pathway structurebelow its constituent material transition temperature.

Other embodiments of the present invention feature an apparatus forretention and transport of elongated materials in a rolling millcoil-forming laying head system comprising an elongated hollow pathwaystructure defining an inner surface for transport of elongated materialstherein, with uniform physical properties along its length. The uniformproperties may be facilitated by bending the pathway structure below thetransition temperature of its constituent materials, and preferably atnear ambient temperature.

Additional embodiments of the present invention feature a method forforming an apparatus for retention and transport of elongated materialsin a rolling mill coil-forming laying head system, by providing anelongated hollow pathway structure defining an inner surface fortransport of elongated materials therein; and bending the pathwaystructure below its constituent material transition temperature. Bendingmay be performed with an automated bending machine that executes bendinginstructions under control of an industrial or other controller, whichin sonic embodiments is a CNC controller. The bending instructions maybe modified to correct for differences between a desired bending profileand an actual bending profile, so that future manufactured pathwaystructures conform to the desired profile specifications.

The features of aspects of the present invention may be applied jointlyor severally in any combination or sub-combination by those skilled inthe art. Further features of aspects and embodiments of the presentinvention and the advantages offered thereby, are explained in greaterdetail hereinafter with reference to specific embodiments illustrated inthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings of the present invention can be readily understood byconsidering the following detailed description in conjunction with theaccompanying drawings, in which:

FIG. 1 shows a coil-forming apparatus including a laying head pipe pathformed via methods of the present invention;

FIG. 2 shows a perspective view of prototype laying head pipe pathformed via methods of the present invention;

FIG. 3 shows a perspective view of an alternative embodiment laying headpipe path to be formed via methods of the present invention;

FIG. 4 shows a perspective view of another alternative embodiment layinghead pipe path to be formed via methods of the present invention;

FIG. 5 shows a partially cut away axial cross-sectional view of thelaying head pipe path of FIG. 4;

FIG. 6 shows an automated bending machine adapted to “cold bend” at nearconstant ambient temperature a laying head pipe path formed via methodsof the present invention;

FIG. 7 shows a controller and control system adapted for operating theautomated bending machine of FIG. 6;

FIG. 8 shows schematically a portion of a laying head pipe path formedvia methods of the present invention, including compensation for springback of the pipe during the bending process; and

FIG. 9 is a flowchart of the methods of the present invention forcompensating for spring back of the pipe during the bending process.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures.

DETAILED DESCRIPTION

To facilitate an understanding of embodiments, principles, and featuresof the present invention, they are explained hereinafter with referenceto implementation in illustrative embodiments. In particular, they aredescribed in the context of being a method of manufacturing a layinghead pipe path elongated structure to a desired profile or shape belowits constituent material transition temperature, desirably below 572° F.(˜300° C.), and preferably near ambient temperature. “Near ambienttemperature” means temperature change attributable to internal elongatedstructure heating during the bending process. The pathway structure orpipe temperature change during the present invention bending process ismuch lower than conventional hot bending temperature change, withstarting temperature of approximately 1922° F. (˜1050° C.), subsequenttemperature drop to approximately 1382° F. (˜750° C.) during therelatively slow manual bending process and ultimate cooling to ambienttemperature. By forming pathway structure or pipe apparatuses below thetransition temperatures of their constituent materials (preferably nearambient temperature) there is less likelihood of changes and variancesin their physical properties, leading to more consistently manufacturedproducts. Embodiments of the present invention, however, are not limitedto use in the described systems or methods.

As wire rod mills attempt to produce product at higher speeds, theservice life of the laying head path material becomes a critical factor.Attempts have been made throughout the years to modify the mathematicalequation that defines the laying head path as well as modifying thematerial from which the laying head path is manufactured, but theprocess by which the laying head path is manufactured has not changed.It is known that the industry standard process currently being used(i.e., heating a tube to an elevated temperature above constituentmaterial transition temperature and manually bending it on a fixture)can have detrimental effects on the mechanical properties of the basematerial. It is also known that changes in the base material of the pipecan result in different amounts of spring-back as the material cools,altering the elongated structure profile dimensions. These dimensionaldifferences are not realized until the cooled, bent pipe is removed fromthe bending fixture and an attempt is made to install the elongatedstructure in the coil forming laying head system equipment. A failedinstallation attempt results in lost maintenance time and remediationeffort to re-bend the path/pipe elongated structure to conform to thedesired profile dimensions.

Laying Head System Overview

Referring to FIGS. 1-5, the coil-forming apparatus laying head system 30coils rolled elongated material, such as for example hot rolled steel.Elongated material that is advancing at a speed that may be as high asor greater than approximately 500 feet/second (150 m/sec), is receivedin the laying head system 30 intake end 32 and discharged in a series ofcontinuous coil loops at the discharge end 34, whereupon the coils aredeposited on a conveyor (not shown).

The laying head system 30 comprises a rotatable quill 50 and elongatedpath structure 60 that is attached to a pipe path support 70 by claims71. The path 60 defines a hollow elongated cavity to enable transport ofthe material elongated material. Aspects of the present invention allowthe path to comprise a laying head pipe; indeed, the path 60 mayoccasionally be referred to as a laying head pipe herein.

The quill 50 can have a generally horn shape that is adapted to rotateabout an axis. The path 60 has a generally helical axial profile ofincreasing radius, with a first end 62 that that is aligned with therotational axis of quill 50 and receives elongated material. The path 60has a second end 64 that is spaced radially outwardly from and generallytangential to the quill 50 rotational axis and thus discharges theelongated material generally tangentially to the periphery of therotating quill. The path 60 is coupled to the pipe support 70 by clamps71. The pipe support 70 is in turn coupled coaxially to the quill 50, sothat all three components rotate synchronously about the quillrotational axis. As illustrated in FIG. 1, as elongated material isdischarged from the second end 64, it is directed into a ring guide 80and its guide trough channel 84, having a helical pitch profile, such asthat described in commonly owned U.S. Pat. No. 6,769,641. As theelongated, material is advanced through the ring guide 80 it iscontinued to he conformed into a continuous loop helix. Ring guide 80 iscoupled to the pipe support 70 and rotates coaxially with the quill 50.

Stationary end ring 90 has an inner diameter that is coaxial with thequill 50 rotational axis and circumscribes the laying path/pipe 60second end 64 as well as the ring guide 80. The end ring 90 counteractscentrifugal force imparted on the elongated material M as it isdischarged front the laying head pipe 60 second end 64 and advancesalong the ring guide 80 helical trough channel 84 by radiallyrestraining the material within the end ring inner diameter guidesurface.

When operating the coil-forming laying head system 30 the quill 50rotational speed can be selected based upon, among other factors, theelongated material structural dimensions and material properties,advancement speed, desired coil diameter and number of tons of elongatedmaterial that can be processed by the laying head pipe without unduerisk of excessive wear. The path/pipe 60 elongated structure isperiodically replaced. As shown in FIG. 2 the laying head path/pipe 60has an interior inner surface 66, which is subjected to relativelyhigher wear rates than other portions of the pipe.

The owner of the present application has other applications, citedabove, which are directed to laying head path/pipe elongated structuresthat incorporate wear resistant zones. In FIG. 3 the laying headpath/pipe 60′ is of laterally joined segmented construction, comprisingthree axially joined segments 61A′, 61B′ and 61C′ which may havedifferent physical properties. For example, segments 61A′ and 61C′ maycomprise steel tubing and segment 61B′ may comprise superalloy tubing,with the segments joined to each. other by weld beads. In FIGS. 4 and 5the laying head path/pipe 60″ embodiment has a multi-layer nestedconstruction, with three layers 61″, 65″ and 68″. The inner surface 66″is defined by an axially joined segments 68A″, 68B″ and 68C″, though aunitary solid inner layer can be substituted for the shown segmentedlayer. In the FIGS. 4 and 5 embodiments the outer layer 61″ isrelatively thin-walled steel construction. The intermediate layer 65″ isconstructed of tubular aluminum and the inner layer 68″ is constructedof stainless steel, super alloy, hardened steel or segmentedcombinations of any of them. The laying head path/pipe pathwaystructure, including the embodiments 60, 60′, 60″ herein, is constructedof relatively thick-walled elongated material, such as pipe, typicallyhaving an outer diameter “OD” between approximately 50 mm-60 mm (1.97in-2.36 in) and an inner diameter “ID” between approximately 10 mm-40mm. (0.39 in-1.57 in). Given, the different physical properties betweenthe steel, stainless steel, aluminum and superalloy portions, and therelatively large wall thickness, preheating and manually bending thejoined segments into the desired path/pipe 60′ profile is challenging,for among other reasons different temperature/plasticity and meltingpoint properties of each material.

Below Transition Temperature Laying Head Pipe Path Bending

Aspects of the present invention relate to a method of manufacturing alaying head pipe pathway, including pathways constructed of axiallyjoined segments and/or multi-layer nested layers. In some embodiments,the method can produce a laying head path at constant, near ambienttemperature, thus eliminating the need for heating the tube to hightemperatures above its constituent material transition temperature, andresulting detrimental impact on the mechanical properties of the basematerial(s). Elimination of elongated pathway structure high temperaturepre-heating facilities use of multi-layer and multiple abutting segmentfabricated pathway construction, where respective portions havedifferent materials and physical properties, such as meltingtemperature.

In some embodiments, shown in FIGS. 6 and 7, the manufacturing method ofthe present invention utilizes known automated bending machinery 200under known computer numerical control (CNC) controller 210 to definethe path 60 profile mathematically, so that future changes to the pathprofile simply require a change to the equipment controller programinstruction set stored in the controller's physical or virtualcontroller platform 100. Once an automated bending instruction set isoptimized to manufacture laying head path elongated structures that arein conformity with desired profile specifications, additional conformingstructures can be readily fabricated quickly and easily, withoutconstruction variances inherent in manually hot-formed conventionallaying head system paths.

Referring to FIG. 7, the physical or virtual controller platform 100includes a processor 110 and a controller bus 120 in communicationtherewith. Processor 110 is coupled to one or more internal or externalmemory devices 130 that include therein operating system 140 andapplication program 150 software module instruction sets that areaccessed and executed by the processor, and cause the automated bendingmachinery 200 to perform bending operations on the laying head path/pipe60, 60′, 60″, etc.

While reference to an exemplary controller platform 100 architecture andimplementation by software modules executed by the processor 110, it isalso to be understood that the present invention may be implemented invarious forms of hardware, software, firmware, special purposeprocessors, or a combination thereof. Preferably, aspects of the presentinvention are implemented in software as a program tangibly embodied ona program storage device. The program may be uploaded to, and executedby, a machine comprising any suitable architecture. Preferably, themachine is implemented on a computer platform having hardware such asone or more central processing units (CPU), a random access memory(RAM), and input/output (I/O) interface(s). The computer platform 100also includes an operating system and microinstruction code. The variousprocesses and functions described herein may be either part of themicroinstruction code or part of the program (or combination thereof)which is executed via the operating system. In addition, various otherperipheral devices may be connected to the computer/controller platform100.

It is to be understood that, because some of the constituent systemcomponents and method steps depicted in the accompanying controller 210and control platform 100 figures are preferably implemented in software,the actual connections between the system components (or the processsteps) may differ depending upon the manner in which the presentinvention is programmed. Specifically, any of the computer platforms ordevices may be interconnected using any existing or later discoverednetworking technology and may also all be connected through a largernetwork system, such as a corporate network, metropolitan network or aglobal network, such as the Internet.

Computer/controller platform 100 receives input communications from oneor more external input devices via respective communications pathways I′directly or indirectly through input interface 160, that in turn candistribute the input information via the controller bus 120. Outputinterface 180 facilitates direct or indirect communication with one ormore output devices, such as the automated bending machine 200, viaassociated communications pathways O′. As shown in FIG. 7 the exemplarycontroller platform 100 has a communications interface 170 forcommunication with other external devices no a shared external data bus,such as the data bus 212, so that input communications I′ and outputcommunications O′ are communicated among the CNC controller 210, theautomated bending machine 200, a host communications server orworkstation 214, instruction set storage device 216 and human machineinterface (HMI) 216. Exemplary CNC controller 210 output communicationsO′ include instruction sets to the automated bending machine 200 forbending pipe or other elongated structures into a desired profile for alaying head pipe/path 60, 60′, 60″ and 160.

In some aspects of the present invention, an automated bending machine200, such as a machine manufactured by Star Technology Srl, of BresciaItaly, can be used to bend a hollow pipe of one or more layers and/or oflaterally joined segments into a particular shape for use as a layinghead pipe path. Aspects of the present invention, utilizing an automatedbending machine 200, permit the desired profile/shape of the laying headpipe/path 60, 60′, 60″ and 160, which is generated when the hollow pipeis at constant ambient temperature, removing the requirement of heatingthe hollow pipe and the bending it into the desired shape. The StarTechnology automated bending machine can push the hollow pipe through apair of opposing grooves that can rotate and angle as the hollow pipe isforced there between, whereby as the hollow pipe exits the grooves thedesired shape of the laying head pipe is generated. A prototype ofexemplary laying head path/pipe 60 was formed on an automated bendingmachine under CNC control, using thin-wailed steel tubing. However, inother embodiments, the automated bending machine should have sufficientpush and bend arm power, for example 10,000 kg (about 22,000 pounds ofpush), in order to bend the exemplary, relatively thick walled layinghead path/pipes 60′ and 60″, having an outer diameter betweenapproximately 50 mm-60 mm (1.97 in-2.36 in) and an inner diameterbetween approximately 10 mm-40 mm (0.39 in-1.57 in).

The method of forming an exemplary laying head pipe pathway 60, 60′,60″, 160 comprises, providing an elongated, hollow tube or otherelongated structure and forcing the tube through a grooved channel inthe automated bending machine 200 that can angle the tube to form aparticular three-dimensional profile or shape. There is no need to heatthe tube to generate the desired shape. This method has the additionaladvantage that elements in the forming machine 200 and/or the CNCcontroller 210 programming can be adjusted to compensate for differentmaterial characteristics, to insure that the actual final bent profileof the laying pipe matches the desired profile. For example, the layinghead path/pipe 160, shown in FIG. 8, has suffered “spring-back” duringthe bending process, so that after the tube material relaxes or springsback partially to its prior straight, unbent profile, the finalresultant actual bent profile angle θ_(A) is shallower than the desiredbent profile angle θ_(D) by angle correction factor θ_(C).

The laying head path/pipe 160 bending instructions utilized by theautomatic bending machine 200 and provided by the CNC controller 210 aremodified to include the correction factor θ_(C), so that subsequentlybent elongated pathway structures conform to the desired bending profileθ_(D). Referring to FIGS. 7 and 9, an initial set of bendinginstructions are created at step 300, such as in the work station 214 orretrieved from storage device 216, and utilized by the bending machine200 to bend a blank elongated structure into a laying head path/pipe 160at near ambient temperature in step 310. If the laying head path/pipe160 bending process requires initial pre-heating of the blank elongatedstructure below its constituent material transition temperature—forexample below 572° F. (˜300° C.)—the laying head path/pipe 160 is formedat a sufficiently low temperature to minimize change in the pathwaymaterial properties. The now bent laying head path/pipe 160 is measuredto determine whether the actual bend angle θ_(A) or other measuredprofile dimension differs from the desired bend angle θ_(D) at step 330.If the actual bend angle or other measured profile dimension meetsdesired specifications, the bending instructions are validated andconfirmed for storage and future reference when bending any subsequentlaying head paths/pipes 160 requiring the same dimensions. Thus futurebent paths/pipes 160 can be bent with good confidence that they willmeet desired dimensional specifications and that they will have uniformconstruction. Conversely if at step 330 it is determined that themeasured profile dimension bend angle θ_(A) differs from. the desiredbend angle θ_(D) the correction factor θ_(C) is determined at step 340and used to modify the initial or prior bending instructions at step350. The bending step 310 is repeated with the modified bendinginstructions of step 350 and the bent tube measured at step 320. Thesteps 310-350 are repeated sequentially to generate new modified bendinginstructions until the actual bending profile θ_(A) conforms to thedesired bending profile θ_(D). Thereupon the modified instructions thatachieved the desired bending profile conformity are stored at step 360for use in future laying head path/pipe elongated structure 160 bendingoperations.

Although various embodiments that incorporate the teachings of thepresent invention have been shown and described in detail herein, thoseskilled in the art can readily devise many other varied embodiments thatstill incorporate these teachings. The invention is not limited in itsapplication to the exemplary embodiment details of construction and thearrangement of components set forth in the description or illustrated inthe drawings. The invention is capable of other embodiments and of beingpracticed or of being carried out in various ways. Also, it is to beunderstood that the phraseology and terminology used herein is for thepurpose of description and should not be regarded as use of “including,”“comprising,” or “having” and variations thereof herein is meant toencompass the items listed thereafter and equivalents thereof as well asadditional items. Unless specified or limited otherwise, the terms“mounted,” “connected,” “supported,” and “coupled” and variationsthereof are used broadly and encompass direct and indirect mountings,connections, supports, and couplings. Further, “connected” and “coupled”are not restricted to physical or mechanical connections or couplings.

What is claimed is:
 1. An apparatus for retention and transport ofelongated materials in a rolling mill coil-forming laying head systemcomprising an elongated hollow pathway structure defining an innersurface for transport of elongated materials therein, the apparatusformed by the process of bending the pathway structure below itsconstituent material transition temperature.
 2. The apparatus of claim 1having an inner layer defining the inner surface and a retention layerfor retaining the inner layer, formed by the process of nesting theinner and outer layers prior to the bending step.
 3. The apparatus ofclaim 1, the elongated hollow pathway structure comprising a segmentedconstruction formed by the process of laterally abutting adjoiningsegments prior to the bending step.
 4. The apparatus of claim 1, thebending step performed on an automated bending machine.
 5. The apparatusof claim 1, the bending step performed at near ambient temperature. 6.The apparatus of claim 1, the bending step performed below 572° F.(˜300° C.).
 7. An apparatus for retention and transport of elongatedmaterials in a rolling mill coil-forming laying head system comprisingan elongated hollow pathway structure defining an inner surface fortransport of elongated materials therein, with uniform physicalproperties along its length.
 8. The apparatus of claim 7, the uniformphysical properties comprising uniform hardness along the inner surface.9. The apparatus of claim 8, the uniform physical properties selectedfrom the group consisting of hardness, surface finish, center ofrotating mass, dimensions, melting temperature and weight per unitlength.
 10. The apparatus of claim 7, the pathway structure comprising apipe having an outer diameter between approximately 50 mm-60 mm (1.97in-2.36 in) and an inner diameter between approximately 10 mm-40 mm(0.39 in-1.57 in).
 11. A method for forming an apparatus for retentionand transport of elongated materials in a rolling mill coil-forminglaying head system, comprising: providing an elongated hollow pathwaystructure defining an inner surface for transport of elongated materialstherein; and bending the pathway structure below its constituentmaterial transition temperature.
 12. The method of claim 11, the bendingstep performed at near ambient temperature.
 13. The method of claim 11,the bending step performed without applying external heat to the pathwaystructure.
 14. The method of claim 11, the bending step performed on anautomated bending machine that executes stored bending instructions toconform the pathway structure to a desired profile.
 15. The method ofclaim 14, the pathway structure comprising a pipe having an outerdiameter between approximately 50 mm-60 mm (1.97 in-2.36 in) and aninner diameter between approximately 10 mm-40 mm (0.39 in-1.57 in). 16.The method of claim 14, further comprising after the bending step:comparing the bent pathway structure actual bent profile with thedesired profile; modifying the stored bending instructions to correctfor differences between the respective profiles, if the actual bentprofile does not conform to the desired profile; repeating the bending,comparing and instruction modifying steps until the pathway structureactual bent profile conforms to the desired profile; storing modifiedsecond bending instructions that conform the actual and desiredprofiles; and bending a plurality of pathway structures with the secondbending instructions.
 17. The method of claim 16, the bending stepperformed at near ambient temperature.
 18. The method of claim 16, thebending step performed without applying external heat to the pathwaystructure.
 19. The method of claim 16, further comprising bending theplurality of pathway structures with uniform physical properties alongeach of their respective lengths, selected from the group consisting ofhardness, surface finish, center of rotating mass, dimensions, meltingtemperature and weight per unit length.
 20. The method of claim 16, thepathway structure comprising a pipe having an outer diameter betweenapproximately 50 mm-60 mm (1.97 in-2.36 in) and an inner diameterbetween approximately 10 mm-40 mm (0.39 in-1.57 in).